The present invention relates to a system for converting audio signals to a visual display and more particularly to a television sound display system. Systems for displaying interpretations of audio signals are known and, for example, represented by U.S. Pat. Nos. 2,804,500 to Giacoletto and 3,604,852 to Weintraub. An improvement over these two systems wherein a standard color television receiver and audio source are employed without modification is illustrated in U.S. Pat. No. 3,723,652 to Alles et al. All three of these systems perform a frequency separation on an audio signal employing some type of filtering scheme. The Weintraub system controls both intensity and beam deflection in a cathode ray tube as a function of a sound spectral content while the Alles et al system employs an internal pattern generator in conjunction with the audio signals. Giacoletto provides different horizontal scanning rates depending upon the type of color input to a color cathode ray tube. The prior art systems lack simplicity and may require internal connections within the television receiver. Color bar generators as color television test equipment are, of course, known but do not provide a color bar display in accordance with an audio signal.
It is accordingly one object of the present invention to provide an audio-visual convertor characterized by its economy of manufacture.
Another object of the present invention is to provide apparatus for generating a display upon the screen of a television receiver requiring no internal connections to or modifications of the existing television receiver circuitry.